The following descriptions and examples are not admitted to be prior art by virtue of their inclusion in this section.
Downhole acoustic investigation involves studying the structure of a subterranean formation based on acoustic waves measured at various locations in a borehole via sonic logging tools. The acoustic waves result from seismic activities involving natural or controlled events. Seismic techniques utilize an array of sensors arranged within a well, e.g. installed downhole in the well to benefit from low acoustic noise, and those techniques may comprise vertical seismic profiling, cross-well profiling, or single well profiling.
Conventional sonic logging tools are composed of transmitters and receivers. Transmitters generate acoustic waves that propagate through fluid and formation prior to the receivers (acoustic sensors) detecting such propagations. Some acoustic monitoring techniques utilize shuttles equipped with geophones or accelerometers coupled to the formation and decoupled from a body of the logging tool. However, the ability to couple sensors to the formation is limited by the size of the sensor packaging and the compliance of the formation. The technique also may have limits with respect to the frequency bandwidth of the acquired signal while relying on complex tool architecture to ensure the desired coupling. The signal is acquired while the logging tool is stationary and the sensors are anchored to the formation. As a result, movement of the logging tool to the next depth of measurement involves a complex process of releasing the anchoring, moving the logging tool, and re-anchoring the sensors in contact with the formation.